text: """Tests for db backends
  
  Authors:
  
  * Min RK
  """
  
  #-------------------------------------------------------------------------------
  #  Copyright (C) 2011  The IPython Development Team
  #
  #  Distributed under the terms of the BSD License.  The full license is in
  #  the file COPYING, distributed as part of this software.
  #-------------------------------------------------------------------------------
  
  #-------------------------------------------------------------------------------
  # Imports
  #-------------------------------------------------------------------------------
  
  from __future__ import division
  
  import logging
  import os
  import tempfile
  import time
  
  from datetime import datetime, timedelta
  from unittest import TestCase
  
  from IPython.parallel import error
  from IPython.parallel.controller.dictdb import DictDB
  from IPython.parallel.controller.sqlitedb import SQLiteDB
  from IPython.parallel.controller.hub import init_record, empty_record
  
  from IPython.testing import decorators as dec
  from IPython.zmq.session import Session
  
  
  #-------------------------------------------------------------------------------
  # TestCases
  #-------------------------------------------------------------------------------
  
  
  def setup():
      global temp_db
      temp_db = tempfile.NamedTemporaryFile(suffix='.db').name
  
  
  class TaskDBTest:
      def setUp(self):
          self.session = Session()
          self.db = self.create_db()
          self.load_records(16)
      
      def create_db(self):
          raise NotImplementedError
      
      def load_records(self, n=1, buffer_size=100):
          """load n records for testing"""
          #sleep 1/10 s, to ensure timestamp is different to previous calls
          time.sleep(0.1)
          msg_ids = []
          for i in range(n):
              msg = self.session.msg('apply_request', content=dict(a=5))
              msg['buffers'] = [os.urandom(buffer_size)]
              rec = init_record(msg)
              msg_id = msg['header']['msg_id']
              msg_ids.append(msg_id)
              self.db.add_record(msg_id, rec)
          return msg_ids
      
      def test_add_record(self):
          before = self.db.get_history()
          self.load_records(5)
          after = self.db.get_history()
          self.assertEqual(len(after), len(before)+5)
          self.assertEqual(after[:-5],before)
          
      def test_drop_record(self):
          msg_id = self.load_records()[-1]
          rec = self.db.get_record(msg_id)
          self.db.drop_record(msg_id)
          self.assertRaises(KeyError,self.db.get_record, msg_id)
      
      def _round_to_millisecond(self, dt):
          """necessary because mongodb rounds microseconds"""
          micro = dt.microsecond
          extra = int(str(micro)[-3:])
          return dt - timedelta(microseconds=extra)
      
      def test_update_record(self):
          now = self._round_to_millisecond(datetime.now())
          # 
          msg_id = self.db.get_history()[-1]
          rec1 = self.db.get_record(msg_id)
          data = {'stdout': 'hello there', 'completed' : now}
          self.db.update_record(msg_id, data)
          rec2 = self.db.get_record(msg_id)
          self.assertEqual(rec2['stdout'], 'hello there')
          self.assertEqual(rec2['completed'], now)
          rec1.update(data)
          self.assertEqual(rec1, rec2)
      
      # def test_update_record_bad(self):
      #     """test updating nonexistant records"""
      #     msg_id = str(uuid.uuid4())
      #     data = {'stdout': 'hello there'}
      #     self.assertRaises(KeyError, self.db.update_record, msg_id, data)
  
      def test_find_records_dt(self):
          """test finding records by date"""
          hist = self.db.get_history()
          middle = self.db.get_record(hist[len(hist)//2])
          tic = middle['submitted']
          before = self.db.find_records({'submitted' : {'$lt' : tic}})
          after = self.db.find_records({'submitted' : {'$gte' : tic}})
          self.assertEqual(len(before)+len(after),len(hist))
          for b in before:
              self.assertTrue(b['submitted'] < tic)
          for a in after:
              self.assertTrue(a['submitted'] >= tic)
          same = self.db.find_records({'submitted' : tic})
          for s in same:
              self.assertTrue(s['submitted'] == tic)
      
      def test_find_records_keys(self):
          """test extracting subset of record keys"""
          found = self.db.find_records({'msg_id': {'$ne' : ''}},keys=['submitted', 'completed'])
          for rec in found:
              self.assertEqual(set(rec.keys()), set(['msg_id', 'submitted', 'completed']))
      
      def test_find_records_msg_id(self):
          """ensure msg_id is always in found records"""
          found = self.db.find_records({'msg_id': {'$ne' : ''}},keys=['submitted', 'completed'])
          for rec in found:
              self.assertTrue('msg_id' in rec.keys())
          found = self.db.find_records({'msg_id': {'$ne' : ''}},keys=['submitted'])
          for rec in found:
              self.assertTrue('msg_id' in rec.keys())
          found = self.db.find_records({'msg_id': {'$ne' : ''}},keys=['msg_id'])
          for rec in found:
              self.assertTrue('msg_id' in rec.keys())
      
      def test_find_records_in(self):
          """test finding records with '$in','$nin' operators"""
          hist = self.db.get_history()
          even = hist[::2]
          odd = hist[1::2]
          recs = self.db.find_records({ 'msg_id' : {'$in' : even}})
          found = [ r['msg_id'] for r in recs ]
          self.assertEqual(set(even), set(found))
          recs = self.db.find_records({ 'msg_id' : {'$nin' : even}})
          found = [ r['msg_id'] for r in recs ]
          self.assertEqual(set(odd), set(found))
      
      def test_get_history(self):
          msg_ids = self.db.get_history()
          latest = datetime(1984,1,1)
          for msg_id in msg_ids:
              rec = self.db.get_record(msg_id)
              newt = rec['submitted']
              self.assertTrue(newt >= latest)
              latest = newt
          msg_id = self.load_records(1)[-1]
          self.assertEqual(self.db.get_history()[-1],msg_id)
      
      def test_datetime(self):
          """get/set timestamps with datetime objects"""
          msg_id = self.db.get_history()[-1]
          rec = self.db.get_record(msg_id)
          self.assertTrue(isinstance(rec['submitted'], datetime))
          self.db.update_record(msg_id, dict(completed=datetime.now()))
          rec = self.db.get_record(msg_id)
          self.assertTrue(isinstance(rec['completed'], datetime))
  
      def test_drop_matching(self):
          msg_ids = self.load_records(10)
          query = {'msg_id' : {'$in':msg_ids}}
          self.db.drop_matching_records(query)
          recs = self.db.find_records(query)
          self.assertEqual(len(recs), 0)
      
      def test_null(self):
          """test None comparison queries"""
          msg_ids = self.load_records(10)
  
          query = {'msg_id' : None}
          recs = self.db.find_records(query)
          self.assertEqual(len(recs), 0)
  
          query = {'msg_id' : {'$ne' : None}}
          recs = self.db.find_records(query)
          self.assertTrue(len(recs) >= 10)
      
      def test_pop_safe_get(self):
          """editing query results shouldn't affect record [get]"""
          msg_id = self.db.get_history()[-1]
          rec = self.db.get_record(msg_id)
          rec.pop('buffers')
          rec['garbage'] = 'hello'
          rec['header']['msg_id'] = 'fubar'
          rec2 = self.db.get_record(msg_id)
          self.assertTrue('buffers' in rec2)
          self.assertFalse('garbage' in rec2)
          self.assertEqual(rec2['header']['msg_id'], msg_id)
      
      def test_pop_safe_find(self):
          """editing query results shouldn't affect record [find]"""
          msg_id = self.db.get_history()[-1]
          rec = self.db.find_records({'msg_id' : msg_id})[0]
          rec.pop('buffers')
          rec['garbage'] = 'hello'
          rec['header']['msg_id'] = 'fubar'
          rec2 = self.db.find_records({'msg_id' : msg_id})[0]
          self.assertTrue('buffers' in rec2)
          self.assertFalse('garbage' in rec2)
          self.assertEqual(rec2['header']['msg_id'], msg_id)
  
      def test_pop_safe_find_keys(self):
          """editing query results shouldn't affect record [find+keys]"""
          msg_id = self.db.get_history()[-1]
          rec = self.db.find_records({'msg_id' : msg_id}, keys=['buffers', 'header'])[0]
          rec.pop('buffers')
          rec['garbage'] = 'hello'
          rec['header']['msg_id'] = 'fubar'
          rec2 = self.db.find_records({'msg_id' : msg_id})[0]
          self.assertTrue('buffers' in rec2)
          self.assertFalse('garbage' in rec2)
          self.assertEqual(rec2['header']['msg_id'], msg_id)
  
  
  class TestDictBackend(TaskDBTest, TestCase):
      
      def create_db(self):
          return DictDB()
      
      def test_cull_count(self):
          self.db = self.create_db() # skip the load-records init from setUp
          self.db.record_limit = 20
          self.db.cull_fraction = 0.2
          self.load_records(20)
          self.assertEqual(len(self.db.get_history()), 20)
          self.load_records(1)
          # 0.2 * 20 = 4, 21 - 4 = 17
          self.assertEqual(len(self.db.get_history()), 17)
          self.load_records(3)
          self.assertEqual(len(self.db.get_history()), 20)
          self.load_records(1)
          self.assertEqual(len(self.db.get_history()), 17)
          
          for i in range(100):
              self.load_records(1)
              self.assertTrue(len(self.db.get_history()) >= 17)
              self.assertTrue(len(self.db.get_history()) <= 20)
  
      def test_cull_size(self):
          self.db = self.create_db() # skip the load-records init from setUp
          self.db.size_limit = 1000
          self.db.cull_fraction = 0.2
          self.load_records(100, buffer_size=10)
          self.assertEqual(len(self.db.get_history()), 100)
          self.load_records(1, buffer_size=0)
          self.assertEqual(len(self.db.get_history()), 101)
          self.load_records(1, buffer_size=1)
          # 0.2 * 100 = 20, 101 - 20 = 81
          self.assertEqual(len(self.db.get_history()), 81)
      
      def test_cull_size_drop(self):
          """dropping records updates tracked buffer size"""
          self.db = self.create_db() # skip the load-records init from setUp
          self.db.size_limit = 1000
          self.db.cull_fraction = 0.2
          self.load_records(100, buffer_size=10)
          self.assertEqual(len(self.db.get_history()), 100)
          self.db.drop_record(self.db.get_history()[-1])
          self.assertEqual(len(self.db.get_history()), 99)
          self.load_records(1, buffer_size=5)
          self.assertEqual(len(self.db.get_history()), 100)
          self.load_records(1, buffer_size=5)
          self.assertEqual(len(self.db.get_history()), 101)
          self.load_records(1, buffer_size=1)
          self.assertEqual(len(self.db.get_history()), 81)
  
      def test_cull_size_update(self):
          """updating records updates tracked buffer size"""
          self.db = self.create_db() # skip the load-records init from setUp
          self.db.size_limit = 1000
          self.db.cull_fraction = 0.2
          self.load_records(100, buffer_size=10)
          self.assertEqual(len(self.db.get_history()), 100)
          msg_id = self.db.get_history()[-1]
          self.db.update_record(msg_id, dict(result_buffers = [os.urandom(10)], buffers=[]))
          self.assertEqual(len(self.db.get_history()), 100)
          self.db.update_record(msg_id, dict(result_buffers = [os.urandom(11)], buffers=[]))
          self.assertEqual(len(self.db.get_history()), 79)
  
  class TestSQLiteBackend(TaskDBTest, TestCase):
  
      @dec.skip_without('sqlite3')
      def create_db(self):
          location, fname = os.path.split(temp_db)
          log = logging.getLogger('test')
          log.setLevel(logging.CRITICAL)
          return SQLiteDB(location=location, fname=fname, log=log)
      
      def tearDown(self):
          self.db._db.close()
  
  
  def teardown():
      """cleanup task db file after all tests have run"""
      try:
          os.remove(temp_db)
      except:
          pass
  